|
The power of a lens is -2.5 D. Its focal length will be |
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|
(a) |
100 cm |
(b) |
40 cm |
(c) |
- 40 cm |
(d) |
- 50 cm |
|
The power of a lens is -2.5 D. Its focal length will be |
|||||||
|
(a) |
100 cm |
(b) |
40 cm |
(c) |
- 40 cm |
(d) |
- 50 cm |